A wide range of concentrating technologies exists: among the best known are the parabolic trough, the compact linear Fresnel reflector, the Stirling dish and the solar power tower. Various techniques are used to track the sun and focus light. In all of these systems a working fluid is heated by the concentrated sunlight, and is then used for power generation or energy storage.[11] Thermal storage efficiently allows up to 24-hour electricity generation.[12]
Biomass is biological material derived from living, or recently living organisms. It most often refers to plants or plant-derived materials which are specifically called lignocellulosic biomass.[99] As an energy source, biomass can either be used directly via combustion to produce heat, or indirectly after converting it to various forms of biofuel. Conversion of biomass to biofuel can be achieved by different methods which are broadly classified into: thermal, chemical, and biochemical methods. Wood remains the largest biomass energy source today;[100] examples include forest residues – such as dead trees, branches and tree stumps –, yard clippings, wood chips and even municipal solid waste. In the second sense, biomass includes plant or animal matter that can be converted into fibers or other industrial chemicals, including biofuels. Industrial biomass can be grown from numerous types of plants, including miscanthus, switchgrass, hemp, corn, poplar, willow, sorghum, sugarcane, bamboo,[101] and a variety of tree species, ranging from eucalyptus to oil palm (palm oil).
The waste we generate ends up in landfills, where it decomposes and produces landfill gas made of approximately 50 percent methane. This gas can be captured and used to fuel electric generators. Since large landfills must burn off this gas to reduce the hazards arising from gas buildup, this method of renewable energy is one of the most successful.
“California Looks to Stationary Energy Storage as a Solution to Peaker Plants” • Central California electric utility Pacific Gas & Electric is planning to replace three old natural gas power plants in its network with stationary energy storage installations from Tesla. California is looking to add 1.3 GW of storage to its power grid by 2020. [CleanTechnica]

Solar water heating makes an important contribution to renewable heat in many countries, most notably in China, which now has 70% of the global total (180 GWth). Most of these systems are installed on multi-family apartment buildings and meet a portion of the hot water needs of an estimated 50–60 million households in China. Worldwide, total installed solar water heating systems meet a portion of the water heating needs of over 70 million households. The use of biomass for heating continues to grow as well. In Sweden, national use of biomass energy has surpassed that of oil. Direct geothermal for heating is also growing rapidly.[28] The newest addition to Heating is from Geothermal Heat Pumps which provide both heating and cooling, and also flatten the electric demand curve and are thus an increasing national priority[29][30] (see also Renewable thermal energy).
Most cars on the road today in the U.S. can run on blends of up to 10% ethanol, and motor vehicle manufacturers already produce vehicles designed to run on much higher ethanol blends. Ford, DaimlerChrysler, and GM are among the automobile companies that sell "flexible-fuel" cars, trucks, and minivans that can use gasoline and ethanol blends ranging from pure gasoline up to 85% ethanol (E85). By mid-2006, there were approximately six million E85-compatible vehicles on U.S. roads.[39]
A good match between generation and consumption is key for high self consumption, and should be considered when deciding where to install solar power and how to dimension the installation. The match can be improved with batteries or controllable electricity consumption.[94] However, batteries are expensive and profitability may require provision of other services from them besides self consumption increase.[95] Hot water storage tanks with electric heating with heat pumps or resistance heaters can provide low-cost storage for self consumption of solar power.[94] Shiftable loads, such as dishwashers, tumble dryers and washing machines, can provide controllable consumption with only a limited effect on the users, but their effect on self consumption of solar power may be limited.[94]

Due to increased technology and wide implementation, the global glass fiber market might reach US$17.4 billion by 2024, compared to US$8.5 billion in 2014. Since it is the most widely used material for reinforcement in composites around the globe, the expansion of end use applications such as construction, transportation and wind turbines has fueled its popularity. Asia Pacific held the major share of the global market in 2014 with more than 45% volume share. However China is currently the largest producer. The industry receives subsidies from the Chinese government allowing them to export it cheaper to the US and Europe. However, due to the higher demand in the near future some price wars have started to developed to implement anti dumping strategies such as tariffs on Chinese glass fiber.[58]
The energy it calculates is in kWh per year, the diameter of the wind turbine rotor is in meters, the wind speed is annual average for the turbine hub height in m/s. The equation uses a Weibull wind distribution with a factor of K=2, which is about right for inland sites. An overall efficiency of the turbine, from wind to electrical grid, of 30% is used. That is a reasonable, real-world efficiency number. Here is a table that shows how average annual wind speed, turbine size, and annual energy production relate:
As of 2012, the Alta Wind Energy Center (California, 1,020 MW) is the world's largest wind farm.[107] The London Array (630 MW) is the largest offshore wind farm in the world. The United Kingdom is the world's leading generator of offshore wind power, followed by Denmark.[108] There are several large offshore wind farms operational and under construction and these include Anholt (400 MW), BARD (400 MW), Clyde (548 MW), Fântânele-Cogealac (600 MW), Greater Gabbard (500 MW), Lincs (270 MW), London Array (630 MW), Lower Snake River (343 MW), Macarthur (420 MW), Shepherds Flat (845 MW), and the Sheringham Shoal (317 MW).
Perfect for camping tailgating or when you need Perfect for camping tailgating or when you need power on the go. The FIRMAN P01001 generator features 1050 starting Watts and 1300 running watts. Power is supplied by our Max Pro Series 80cc FIRMAN engine which runs cool and efficient thanks to its Phoenix Fat Head Block. Our Whisper Series ...  More + Product Details Close

By now you are probably thinking “why would these guys tell me the truth? They sell small wind turbines!”. Yup, guilty as charged. We also want happy customers, and the two are not reconcilable unless we are upfront with you, our customer. Truth is, wind turbine sales are a tiny part of our revenue, and while we would regret losing you, we will still be able to put food on our kids’ plates.
Biomass, biogas and biofuels are burned to produce heat/power and in doing so harm the environment. Pollutants such as sulphurous oxides (SOx), nitrous oxides (NOx), and particulate matter (PM) are produced from the combustion of biomass; the World Health Organisation estimates that 7 million premature deaths are caused each year by air pollution.[77] Biomass combustion is a major contributor.[77][78][79]

With that in mind it makes a great deal of sense to use a tilt-up tower for your turbine. It makes maintenance and repairs much safer (on the ground) and cheaper. Crane fees, or having turbine installers hang off the top of a tower for long periods of time, tend to get very expensive. You should also budget for repairs, they will happen. Parts may be free under warranty, your installer’s time is not.


Solar thermal power stations have been successfully operating in California commercially since the late 1980s, including the largest solar power plant of any kind, the 350 MW Solar Energy Generating Systems. Nevada Solar One is another 64MW plant which has recently opened.[34] Other parabolic trough power plants being proposed are two 50MW plants in Spain, and a 100MW plant in Israel.[35]
Environmental impact of wind power includes effect on wildlife, but can be mitigated if proper monitoring and mitigation strategies are implemented.[76] Thousands of birds, including rare species, have been killed by the blades of wind turbines,[77] though wind turbines contribute relatively insignificantly to anthropogenic avian mortality. For every bird killed by a wind turbine in the US, nearly 500,000 are killed by each of feral cats and buildings.[78] In comparison, conventional coal fired generators contribute significantly more to bird mortality, by incineration when caught in updrafts of smoke stacks and by poisoning with emissions byproducts (including particulates and heavy metals downwind of flue gases). Further, marine life is affected by water intakes of steam turbine cooling towers (heat exchangers) for nuclear and fossil fuel generators, by coal dust deposits in marine ecosystems (e.g. damaging Australia's Great Barrier Reef) and by water acidification from combustion monoxides.
Since 2013 the world's highest-situated wind turbine was made and installed by WindAid and is located at the base of the Pastoruri Glacier in Peru at 4,877 meters (16,001 ft) above sea level.[94] The site uses the WindAid 2.5 kW wind generator to supply power to a small rural community of micro entrepreneurs who cater to the tourists who come to the Pastoruri glacier.[95]
Airflows can be used to run wind turbines. Modern utility-scale wind turbines range from around 600 kW to 5 MW of rated power, although turbines with rated output of 1.5–3 MW have become the most common for commercial use. The largest generator capacity of a single installed onshore wind turbine reached 7.5 MW in 2015. The power available from the wind is a function of the cube of the wind speed, so as wind speed increases, power output increases up to the maximum output for the particular turbine.[42] Areas where winds are stronger and more constant, such as offshore and high altitude sites, are preferred locations for wind farms. Typically full load hours of wind turbines vary between 16 and 57 percent annually, but might be higher in particularly favorable offshore sites.[43]
A wind turbine is made up of two major components and having looked at one of them, the rotor blade design in the previous tutorial, we can now look at the other, the Wind Turbine Generator or WTG’s which is the electrical machine used to generate the electricity. A low rpm electrical generator is used for converting the mechanical rotational power produced by the winds energy into usable electricity to supply our homes and is at the heart of any wind power system.
Biomass is biological material derived from living, or recently living organisms. It most often refers to plants or plant-derived materials which are specifically called lignocellulosic biomass.[99] As an energy source, biomass can either be used directly via combustion to produce heat, or indirectly after converting it to various forms of biofuel. Conversion of biomass to biofuel can be achieved by different methods which are broadly classified into: thermal, chemical, and biochemical methods. Wood remains the largest biomass energy source today;[100] examples include forest residues – such as dead trees, branches and tree stumps –, yard clippings, wood chips and even municipal solid waste. In the second sense, biomass includes plant or animal matter that can be converted into fibers or other industrial chemicals, including biofuels. Industrial biomass can be grown from numerous types of plants, including miscanthus, switchgrass, hemp, corn, poplar, willow, sorghum, sugarcane, bamboo,[101] and a variety of tree species, ranging from eucalyptus to oil palm (palm oil).
Above this rated speed, the wind loads on the rotor blades will be approaching the maximum strength of the electrical machine, and the generator will be producing its maximum or rated power output as the rated wind speed window will have been reached. If the wind speed continues to increase, the wind turbine generator would stop at its cut-out point to prevent mechanical and electrical damage, resulting in zero electrical generation. The application of a brake to stop the generator for damaging itself can be either a mechanical governor or electrical speed sensor.

Mr. Trump has said the Paris agreement is a bad deal for the United States and that the country will no longer work toward its pledge of cutting emissions at least 26 percent below 2005 levels by 2025 or contribute money to the climate fund. Former President Barack Obama promised $3 billion over four years and delivered $1 billion before leaving office.


Bioethanol is an alcohol made by fermentation, mostly from carbohydrates produced in sugar or starch crops such as corn, sugarcane, or sweet sorghum. Cellulosic biomass, derived from non-food sources such as trees and grasses is also being developed as a feedstock for ethanol production. Ethanol can be used as a fuel for vehicles in its pure form, but it is usually used as a gasoline additive to increase octane and improve vehicle emissions. Bioethanol is widely used in the USA and in Brazil. Biodiesel can be used as a fuel for vehicles in its pure form, but it is usually used as a diesel additive to reduce levels of particulates, carbon monoxide, and hydrocarbons from diesel-powered vehicles. Biodiesel is produced from oils or fats using transesterification and is the most common biofuel in Europe.

The energy in the wind goes up with the cube of the wind speed. Double the wind speed and you have 2 * 2 * 2 = 8 times the energy! Sit back and let the full weight of that sink in for a moment: It means that even a small difference in annual average wind speed will make a BIG difference in how much your wind turbine will produce: Putting that turbine in a place that has just 10% more wind will net you 1.1 * 1.1 * 1.1 = 1.33 = a full 33% more energy!


Adam Schultz, a senior policy analyst for the Oregon Department of Energy, says he’s more encouraged than ever about the prospects for renewables. Because the Pacific Northwest features large-scale hydropower plants built as part of the New Deal, energy already tends to be less expensive there than the U.S. average. But solar and wind power have “gotten cheaper over the last couple years to the point that I can’t even tell you what the costs are because costs have been dropping so rapidly,” Schultz says. “We have enough sunshine,” he says (presumably referring to the eastern part of the state), “so it’s just a matter of time.”

As of 2018, American electric utility companies are planning new or extra renewable energy investments. These investments are particularly aimed at solar energy, thanks to the Tax Cuts and Jobs Act of 2017 being signed into law. The law retained incentives for renewable energy development. Utility companies are taking advantage of the federal solar investment tax credit before it permanently goes down to 10% after 2021. According to the March 28 S&P Global Market Intelligence report summary, "NextEra Energy Inc., Duke Energy Corp., and Dominion Energy Inc.’s utilities are among a number of companies in the sector contemplating significant solar investments in the near-term. Other companies, including Xcel Energy Inc. and Alliant Energy Corp., are undertaking large wind projects in the near-term, but are considering ramping up solar investments in the coming years."[96]

A 1.5 (MW) wind turbine of a type frequently seen in the United States has a tower 80 meters (260 ft) high. The rotor assembly (blades and hub) weighs 22,000 kilograms (48,000 lb). The nacelle, which contains the generator, weighs 52,000 kilograms (115,000 lb). The concrete base for the tower is constructed using 26,000 kilograms (58,000 lb) reinforcing steel and contains 190 cubic meters (250 cu yd) of concrete. The base is 15 meters (50 ft) in diameter and 2.4 meters (8 ft) thick near the center.[43]


List of books about renewable energy List of countries by electricity production from renewable sources List of geothermal power stations Lists of hydroelectric power stations List of largest hydroelectric power stations List of people associated with renewable energy List of renewable energy companies by stock exchange List of renewable energy organizations List of renewable energy topics by country List of U.S. states by electricity production from renewable sources

^ Jump up to: a b c d Alsema, E.A.; Wild – Scholten, M.J. de; Fthenakis, V.M. Environmental impacts of PV electricity generation – a critical comparison of energy supply options Archived 6 March 2012 at the Wayback Machine. ECN, September 2006; 7p. Presented at the 21st European Photovoltaic Solar Energy Conference and Exhibition, Dresden, Germany, 4–8 September 2006.
If you can turn a wrench and operate an electric drill, you can build this simple generator in two days: one day for chasing down parts, and one day for assembling the components. The four major components include a vehicle alternator with a built-in voltage regulator, a General Motors (GM) fan and clutch assembly (I used one from a 1988 GM 350 motor), a tower or pole on which to mount the generator (15 feet of used 2-inch tubing cost me $20), and the metal to build a bracket for mounting the generator on the tower or pole. If you’re a Ford guy or a Mopar gal, that’s fine — just make sure your alternator has a built-in voltage regulator. You’ll also need some electrical cable or wires to hook the alternator up to your storage batteries. I used 8-gauge, 3-conductor cable pilfered from the oil patch. (And they said the transition from fossil fuels to renewables would take years. Pfft!)
Subsequently, Spain, Italy, Greece—that enjoyed an early success with domestic solar-thermal installations for hot water needs—and France introduced feed-in tariffs. None have replicated the programmed decrease of FIT in new contracts though, making the German incentive relatively less and less attractive compared to other countries. The French and Greek FIT offer a high premium (EUR 0.55/kWh) for building integrated systems. California, Greece, France and Italy have 30–50% more insolation than Germany making them financially more attractive. The Greek domestic "solar roof" programme (adopted in June 2009 for installations up to 10 kW) has internal rates of return of 10–15% at current commercial installation costs, which, furthermore, is tax free.
Through collaboration, smaller buyers can benefit from economies of scale, while larger buyers can continue to see cost benefits while achieving their renewable energy goals. Aggregation allows companies to procure in a mutually beneficial way with relatively little give and take. For that reason, RMI believes this marks “the beginning of a trend,” Haley said.  
With investment subsidies, the financial burden falls upon the taxpayer, while with feed-in tariffs the extra cost is distributed across the utilities' customer bases. While the investment subsidy may be simpler to administer, the main argument in favour of feed-in tariffs is the encouragement of quality. Investment subsidies are paid out as a function of the nameplate capacity of the installed system and are independent of its actual power yield over time, thus rewarding the overstatement of power and tolerating poor durability and maintenance. Some electric companies offer rebates to their customers, such as Austin Energy in Texas, which offers $2.50/watt installed up to $15,000.[96]
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